🔧 WRX - A/C Compressor Replacement

Replacing the A/C compressor on your WRX is mostly a bolt-on job, but the refrigerant must be recovered and the system must be vacuumed and recharged correctly. If the system is opened without proper equipment, you can get injured and the A/C won’t cool (and it’s illegal to vent refrigerant).

Difficulty Level: Advanced | Estimated Time: 3-6 hours

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⚠️ Safety & Precautions

• 🧯 Never vent refrigerant—have the system professionally recovered first.
• 🧤 Wear safety glasses and gloves; refrigerant/oil can freeze-burn skin and eyes.
• 🔥 Work on a cool engine; keep hands away from the radiator fans.
• 🔌 Disconnect the negative battery terminal before unplugging compressor wiring.
• ⚙️ Do not run the A/C with the system empty or open.

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🔧 Required Tools

You'll need the following tools for this repair:

• Safety glasses
• Nitrile gloves
• Floor jack (rated 3-ton minimum)
• Jack stands (rated 3-ton minimum)
• Wheel chocks
• Metric socket set (8mm-14mm)
• 3/8" drive ratchet
• 3/8" drive torque wrench
• Serpentine belt tool
• Flat trim tool
• Pick tool
• Line wrench set (metric)
• A/C manifold gauge set (specialty)
• Vacuum pump (specialty)
• Refrigerant recovery machine (specialty)
• Refrigerant scale (specialty)
• UV leak detector flashlight
• Shop rags

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🔩 Required Parts

HowToo sells all the parts you need for this repair:

• A/C compressor - Qty: 1
• A/C compressor O-ring set - Qty: 1
• R-134a refrigerant - Qty: As required
• A/C compressor oil (manufacturer-specified type) - Qty: As required
• Receiver/drier or desiccant (if serviceable separately) - Qty: 1

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📋 Before You Begin

• 🅿️ Park on level ground, set the parking brake, and chock the rear wheels.
• 🔋 Disconnect the negative battery terminal using a metric socket. Prevents accidental shorts.
• ❄️ Have the A/C refrigerant professionally recovered (or use a recovery machine). Do not continue until the system is fully empty.
• 🧰 If you don’t have a vacuum pump, manifold gauges, and a scale, plan to do the mechanical swap, then tow/drive to a shop for evac and recharge.

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🔨 Step-by-Step Instructions

Follow these steps in order:

Step 1: Recover the refrigerant (required)

• Use a refrigerant recovery machine (specialty) to recover the refrigerant from the high and low service ports.
• Do not crack open any A/C line fittings until the gauges show the system is fully recovered.

Step 2: Raise the front of the car

• Use a floor jack (rated 3-ton minimum) to lift the front.
• Support the car with jack stands (rated 3-ton minimum).

Step 3: Remove the undertray (if equipped)

• Use a flat trim tool to remove plastic clips.
• Use a metric socket set (8mm-14mm) and 3/8" drive ratchet to remove undertray bolts.

Step 4: Remove the drive belt from the A/C compressor

• Use a serpentine belt tool to rotate the tensioner and slip the belt off the A/C compressor pulley.
• Take a quick photo of belt routing.

Step 5: Unplug the compressor electrical connector

• Use a flat trim tool to gently release the connector lock, then unplug it.
• Keep the connector clean and away from oil/dirt.

Step 6: Disconnect the A/C lines from the compressor

• Place shop rags under the compressor to catch any oil.
• Use a line wrench set (metric) to loosen the A/C line fittings/bolts without rounding them.
• Immediately remove old O-rings with a pick tool and discard them.
• Cap/cover open lines to keep moisture out (moisture can ruin the drier and corrode internals).

Step 7: Remove the compressor mounting bolts and remove the compressor

• Use a metric socket set (8mm-14mm) and 3/8" drive ratchet to remove the compressor mounting bolts.
• Carefully lower and remove the compressor from the engine bay.

Step 8: Prepare the new compressor (oil + O-rings)

• If the new compressor is shipped with oil, verify it matches the required oil type. Use only A/C compressor oil (manufacturer-specified type).
• Replace all sealing O-rings using the A/C compressor O-ring set.
• Lightly lubricate each O-ring with A/C compressor oil (manufacturer-specified type) before installation.

Step 9: Install the new compressor

• Position the compressor and start all mounting bolts by hand.
• Use a metric socket set (8mm-14mm) and 3/8" drive ratchet to snug the bolts evenly.
• Use a 3/8" drive torque wrench to finish tightening: Torque to factory specification.

Step 10: Reconnect the A/C lines

• Install the lines carefully to avoid pinching O-rings.
• Use a line wrench set (metric) to tighten fittings/bolts.
• Use a 3/8" drive torque wrench where applicable: Torque to factory specification.

Step 11: Reconnect the electrical connector and reinstall the belt

• Plug the compressor connector back in until it clicks.
• Use a serpentine belt tool to rotate the tensioner and reinstall the belt.
• Visually confirm the belt is seated in every pulley groove.

Step 12: Reinstall undertray and lower the car

• Use a metric socket set (8mm-14mm) and 3/8" drive ratchet to reinstall bolts.
• Use a flat trim tool to reinstall clips.
• Lower the car using the floor jack (rated 3-ton minimum).

Step 13: Evacuate and recharge the A/C system

• Connect the A/C manifold gauge set (specialty).
• Use the vacuum pump (specialty) to pull vacuum and verify it holds (leak check).
• Recharge with R-134a refrigerant by weight using a refrigerant scale (specialty): Charge to the under-hood label specification.

Step 14: Reconnect the battery

• Use a metric socket set (8mm-14mm) to reconnect the negative battery terminal.

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✅ After Repair

• ✅ Start the engine and turn A/C to MAX; confirm the compressor clutch engages and the cabin air gets cold.
• 🔍 Use a UV leak detector flashlight to check for dye/oily residue around the compressor fittings and lines.
• 👂 Listen for belt squeal or grinding; shut off immediately if you hear abnormal noises.
• 🧊 Confirm vent temps improve and pressures look normal on the gauge set (if you have one).

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💰 DIY vs Shop Cost

Shop Cost: $900-$1,800 (parts + labor)

DIY Cost: $350-$900 (parts only)

You Save: $550-$900 by doing it yourself!

Shop labor rates vary but typically run $100-$150/hour. This repair takes a shop approximately 2-4 hours.

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🎯 Ready to get started?

HowToo makes it easy: same-day/2-day shipping on every part, plus all the tools and specialty tools you need! Check out the parts and tools sections below to add everything to your cart.